1. Field of the Invention
The present invention relates to video detection, and more particularly, to a method that is able to reduce power consumption of a gesture sensor, and a related electronic device and sensor array.
2. Description of the Prior Art
A sensing device of recognizing gesture (i.e., gesture sensor) is widely used in a variety of applications, providing an innovative and instinctive way of interacting human with machine, which detects motion of a hand of a user and accordingly issues control commands to a user interface. Generally, the sensing device of recognizing the gesture includes components as shown in FIG. 1. An active light source 110 periodically illuminates the hand and a sensing device 120 periodically detects changes of lights and shadows generated by illumination on the hand. Computation circuit inside the sensing device 120 determines whether the motion of the hand matches specific gesture patterns and accordingly generates control commands. Operating frequencies of the active light source 110 and the sensing device 120 are illustrated in FIG. 2A. When the hand leaves from a sensing covering range V of the sensing system 100, the active light source 110 and the sensing device 120 stop periodically operating. Then, a standby mode is entered such that power consumption can be saved. In the meantime, the active light source temporarily stops illuminating the hand of the user. Also, the sensing device 120 temporarily stops sampling changes of lights and shadows. In order to re-activate the sensing system 100 when the hands enter the sensing covering range again, the active light source 110 and the sensing device 120 intermittently detect whether the hand enter the sensing covering range V again (at a operating frequency which is lower than a operating frequency of the normal operating state). Once there is no change found between the lights and the shadows, the sensing system 100 remains in the standby mode. Otherwise, the sensing system 100 comes back to the normal operating state, performing gesture recognition. Operating frequencies regarding the active light source 110 and the sensing device 120 is illustrated in FIG. 2B.
However, as the active light source 110 and the sensing device 120 intermittently detects changes of the lights and the shadows, re-activation of the sensing system 100 may be delayed if the sensing device 120 cannot capture the motion of the hand immediately (i.e., the hand moves too fast). This is because the sensing system 100 is operated at a relatively low frequency under the standby mode and may miss the motion of the hand. As a result, the user feels delay when trying to re-activate the sensing system from the standby mode.